A bipartisan group of six senators is expected to release an outline for an immigration overhaul next week, at the same time that President Barack Obama will begin his own public push on the issue.

The senators have been working since November, after the 2012 elections, to come up with a set of principles that would be the foundation for a bill. They have set an internal deadline to unveil their principles by Feb. 1, Congressional sources said.

The group includes Republican Sens. John McCain of Arizona, Lindsey Graham of South Carolina and Marco Rubio of Florida, as well as Democratic Sens. Charles E. Schumer of New York, Richard J. Durbin of Illinois and Robert Menendez of New Jersey. Others, such as Sens. Michael Bennet, D-Colo., Jeff Flake, R-Ariz., and Mike Lee, R-Utah, have also attended meetings.

Durbin, the Senate majority whip who has long pushed for passage of legislation that would provide the children of undocumented immigrants a path to citizenship, said Thursday that the group was well on its way to the finish line, but he said more work was needed.

“We’re making progress, and we still have a long way to go.” Durbin said. “Everything so far has been extremely positive.”

“There is a much different mood on the Republican side,” the Illinois Democrat continued, citing the difference Latino voters in swing states made for Democrats in the most recent elections. “If you’re a student of history, you know exactly what’s happening here. You know, new groups to America are not taken seriously until they have political clout.”

Durbin noted that Hispanics in Colorado voted 85 percent for Obama.

“We have a basic agreement on many of the core principles. Now we have to draft it, and that really is — it takes time,” he said.

Durbin said White House has been monitoring the bipartisan negotiations between the senators.

Senate Judiciary Chairman Patrick J. Leahy, D-Vt., whose panel has jurisdiction over the issue, said he expects to hold hearings soon. But he said he wants to be sure he hears from everyone interested in reform — including the president — in order to develop a bipartisan measure with the best chances of becoming law.

“I want to make sure they are all heard,” Leahy stressed.

“I think [the hearings] will be fairly soon because I sense a movement between both Republicans and Democrats that we’ve go to do something on immigration and I am not sure that will be here in an election year, so let’s do it now,” Leahy continued. Though the hearings will likely take place at the full committee level, Schumer is the chairman of the Judiciary Subcommittee on Immigration, Refugees and Border Security.

Frank Sharry, executive director of left-leaning immigration advocacy group America’s Voice, said he expects hearings to take place next month, with a markup in March or April.

Even as the Senate group prepares to unveil its package, Obama is expected to visit Las Vegas on Jan. 29 to lay down a marker on what he wants to see in an immigration overhaul package.

“He will speak about the blueprint that has been available to the public for more than a year,” White House Press Secretary Jay Carney said. “These are the principles that the president believes we can now move forward on together as a nation. What has been absent in the time since he put those principles forward has been a willingness by Republicans, generally speaking, to move forward with comprehensive immigration reform. What he hopes is that that dynamic has changed.”

According to a statement from the White House, at the meeting, “the President made it clear he will continue to lead on this issue, and that he looks forward to working with the Congressional Hispanic Caucus and other key Members of Congress in a bipartisan process to move this debate forward at the earliest possible opportunity.”